[TheForge] Steel Vs. Glass

[A. Vida]

Ed F wrote:
> 
> You can easily scratch steel with glass.  But you can't easilly scratch
> glass with steel.

	Ce?!  I take it you are not aware that this is not at universally
	the case?  Just to give an extreme example, take an M-2 HSS lathe
	tool.  It will scratch glass quite readily but I do not think 
	that there are too many glass compositions that will scratch it
	readily.
> 
> Is the difference in abrasion resistance explained by the ductility,
> brittlness, combination of the two or none of the above?

	You talk of steel and glass as if they were entities with only
	a single set of well defined properties.  Clearly this is not
	the case.  There are literally thousands of different steels.
	Add to them the usually broad continuum of physical properties
	those steels may possess, imparted by physical working, heat
	treating, etc., and you have a very large range of possible
	properties from dead soft (e.g. pure iron) to extremely hard
	(e.g. nitrided steel).